Final answer:
Cable splices in cable trays should be accessible for maintenance and repair. Copper is preferred for splicing due to its malleability and ductility, making it suitable for reliable electrical connections.
Step-by-step explanation:
The question refers to the practices regarding the splicing of cables in cable trays, which is a typical task in electrical installations, especially in industrial or commercial settings. In engineering, particularly electrical engineering, it is essential to adhere to standards and regulations for safety and functionality. Cable splices must be done properly to ensure the integrity and reliability of the electrical system.
For the splices to be accessible, they need to be situated in a position where they can be reached for inspection, maintenance, or repair without requiring structural alterations or hazardous procedures. This requirement ensures future safe interaction with the spliced cables. Although the terms mentioned in the question, such as 'within sight' and 'butt tight', might relate to specific standards or preferences in certain applications, the prime material for splicing is often copper due to its malleability and ductility. Copper's properties make it an excellent choice for splicing because it's easy to shape and join while maintaining good electrical conductivity.
In summary, the standards for cable splicing in cable trays primarily demand the splices to be accessible. Using copper for splices takes advantage of its malleability and ductility, which are advantageous for creating reliable and efficient electrical connections.